Intravascular diseases are commonly treated by relatively non-invasive techniques such as PTA and PTCA. These angioplasty techniques typically involve the use of a balloon catheter. In these procedures, a balloon catheter is advanced through the vasculature of a patient such that the balloon is positioned proximate a restriction in a diseased vessel. The balloon is then inflated and the restriction in the vessel is opened. In other uses a catheter may be used to delivery an endoprosthesis such as a stent, graft, vena cava filter or other implantable device. Where an implantable device is to be delivered into a body lumen the catheter may include one or more inflatable portions or balloons.
Many procedures make use of a guide catheter positioned within the vascular system of a patient. The guiding catheter assists in transporting a balloon dilation catheter, or other form of treatment catheter, to the portion of the vessel requiring treatment or inspection. The guide catheter is urged through the vasculature of the patient until its distal end is proximate the restriction. The balloon catheter may then be fed through a lumen in the guide catheter.
In delivering a balloon expandable medical device, it is important that the medical device be accurately positioned on the body or working portion of the balloon. Failure to properly position the medical device on the balloon may result in a non-uniform expansion of the medical device.
Unfortunately, the proper positioning of such a medical device on a balloon catheter can be a challenging task because the medical device is typically mounted on an uninflated balloon. In the uninflated state of the balloon, it is difficult to discern where the proximal and distal cones end and where the body portion of the balloon begins.
Numerous devices have been employed to help secure an expandable medical device, such as a stent onto a catheter. Such devices include pull-back sheathes which extend over the entire stent to retain the stent to a portion of the catheter. Some examples of sheathes may be found in U.S. Pat. No. 5,772,669, U.S. Pat. No. 5,868,755, U.S. Pat. No. 4,732,152, U.S. Pat. No. 4,848,343, U.S. Pat. No. 4,875,480, U.S. Pat. No. 5,662,703, U.S. Pat. No. 5,690,644, WO 94/15549 and others. With many retraction systems, it is necessary to move a portion of a manifold or other retraction device a distance at least equal to the length of the retractable sheath to retract the sheath.
Some systems have been developed which avoid the need for retractable sheathes by providing a stent delivery catheter with one or more self-retracting sleeves. Some examples of delivery catheters having sleeves which may be self-retractable are described in: U.S. Pat. No. 4,950,227, U.S. Pat. No. 5,403,341, U.S. Pat. No. 5,108,416, and others.
In U.S. Pat. No. 4,950,227 to Savin et al., an inflation expandable stent delivery system includes a sleeve which overlaps the distal or proximal margin (or both) of the stent during delivery. During inflation of the stent at the deployment site, the stent margins are freed of the protective sleeve(s). U.S. Pat. No. 5,403,341 to Solar, relates to a stent delivery and deployment assembly which uses retaining sheaths positioned about opposite ends of the compressed stent. The retaining sheaths of Solar are adapted to tear under pressure as the stent is radially expanded, thus releasing the stent from engagement with the sheaths. U.S. Pat. No. 5,108,416 to Ryan et al., describes a stent introducer system which uses one or two flexible end caps and an annular socket surrounding the balloon to position the stent during introduction to the deployment site.
Still other systems are known which employ a variety of alternative means for retaining a stent on a catheter and/or balloon prior to deliver. For example, the stent delivery system of U.S. patent application Ser. No. 09/697,608 includes stent securement hubs which engage portions of a stent disposed about a catheter, and EP 696,447 describes delivery catheters comprising runners for circumferentially supporting a prosthesis.
Still other systems have been developed which employ surface features on the catheter surface to aid in retaining the stent thereabout. Some examples of systems having unique surface features are described in: WO 00/57816 wherein catheters are described having a textured or roughened surface for retaining a medical device thereon, U.S. Pat. No. 6,258,099 which describes catheter balloons having engagement protrusions, and U.S. Pat. No. 6,048,350 which describes delivery systems employing a combination of securement hubs and balloon segments to aid in retaining a stent there on.
An advantage of providing a stent delivery catheter with surface features that promote stent retention prior to delivery is that the profile of the catheter may be minimized as there may be no need to include additional sheathes, sleeves or other members which would otherwise overlap the stent and increase the profile of the catheter. Another advantage of providing a catheter with stent retaining surface features is that by removing the need for retractable members, the need for relatively bulky or complex retraction systems is likewise removed, thereby providing a delivery system which may be much more simple and safer to use.
Expandable medical devices such as stents have a wide variety of shapes, sizes and configurations. For example, it is known that a stent having a particular strut pattern may have performance characteristics which are significantly different than a stent having a different strut pattern. As a result, it would be desirable to provide individual catheters with varying types of surface feature patterns in order to maximize the effectiveness of the surface pattern in retaining a stent of a particular configuration. Unfortunately, typical manufacturing processes of catheters do not readily lend themselves to individualized production of different catheter types.
Some, catheters and/or balloons are formed of extruded material which is then shaped or molded into a final shape. Providing dozens of different molds for a wide range of surface feature patterns may be cost prohibitive as well as extremely inefficient from a manufacturing perspective. Thus, it would be desirable to provide a method for applying a unique surface feature pattern to catheters, and particularly to balloons which may be cheaply and easily employed on an individual basis.
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims.